SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff39da92126780d2ef821dfea0b42a074277bba97d7378f33c699298e6079209' 
  AND token = 'Uan9sLR0zq71zzVVyjIG1VsvUSFmp1VSLRdoD4ts4js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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