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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5d29203b67902c4da4d7db2a2ac749d0e77081b48db8fd50650e5b7a4cc7cb5' 
  AND token = 'QSAIcdvDIkfXqQLJcCn8r1QP+RNm3j+BqBKCX3CDnYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}