SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ecc975de3cddcd529c1fe21df9312716b2538e73426fefe64d2b528728c61f2' 
  AND token = 'PkNkHKgpf8vdEeDj7f/JL8fUYO2F9IJL1jdRbULsHQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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