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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '683ddf1e0b61d4fa0970c9c761fbdde5319747ee1bd2d942d9ac369c777ac351' 
  AND token = 'h8jgDsIzg3J8L41DQeCiBzwWCa1ILRqclNzd60vJMq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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