SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b2b4100a30e3db236e224ced704f89369f045501fb1333395cb2de58ab03e2' 
  AND token = '1yGoqL8VuvOUmy7/yojZb44PCzFWmv9ru5UTpwi79rA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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