SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6753b62b2c69a12efc404913e6f3b3cdc5cf2b25139a0ef0128a30430a2cefe8' 
  AND token = 'yqqmXF4jGR37qNukagWTVWpJup2rF8JdVoA9Cucs+i8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}