SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd218ffa751d578575bbad33dc66f2363c974aec736ef93f9d08906ed742dfeee' 
  AND token = 'mTstl2ONYOSONRtTGqQOmAXSAk8sPJlzUKK3ZPwWhQU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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