SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fcd8f5b3d468c7d75783d39b3236c9383a281f03c8474699f5c07510edd8932' 
  AND token = 'z5+hoEqg9nFlrr6rw0DHx1L/p+X/3R5sYz/qatzAyzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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