SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '451f1975d7288c26535e425589299ce5c76a6808f1445db4ef9df9002901658d' 
  AND token = 'z3/IkTpQyukZXK9g7yjrx6C2gZUouUqvQKfYYMMEDDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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