SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53210fa40f4320d8649e1d40fa5ae91a3f03cc2539cc03c8a4316f3671455f11' 
  AND token = 'Elu7tuKOuMqTwA2UTrtMDkP348KSHYV9DvTQsWNmogM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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