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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b26cd913ae1c6efe304c37d40e340a359a9a0d749fd8e36305c1fe7e0d4453ec' 
  AND token = 'DaMHG9AaYpgwAWGQfYMawDPyfcFJmM6FpGqLAVK5jWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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