SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31d1bfa1ed8a561a3e424a9244997c403b11433919bbb33e096011e499e89dde' 
  AND token = 'yjzVnpKdsBHIzn6FkkYreHM7/wIHrxsfdrk9EFRqVDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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