SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e64295d502e75b5dc66dc319431b1808cead046857de25a5c93fc3ab016c34' 
  AND token = 'UY8snFw88e2+4eaF0bT5MWKe3TxDHoCnGrNauMXqP6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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