SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6de1b5845f34744cfad088982406e366f006de2728f8c2c39fce1a7ff44c6b8' 
  AND token = 'IP2CGKf77NJbUxBAAxrNVjuX7eRfZc5BcjwMU/CqZ0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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