SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'faf284c64a49f0a2dcf894f56d63d7f1de5395a5a4e6197a53489d9148749614' 
  AND token = 'PUYxGvsl+60Lj5/HI2Nw5pjvakW6QBqedEqhfo9LOg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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