SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '71271a60d5ab10fda62ddb0a00d1087fe8ad04554153dd61e80eea1e4a200488' 
  AND token = '4so5rxp6YPWaLHfASsTz5BvqkKQHcfjGJR9wCOZP6+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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