SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90ead21fb342a4702a718c622fffdf62685f288725efe41009d2948d86b9d7b2' 
  AND token = 'qGHHzCpu1LTKudvMKAmgY0rI0jElL69wYVGqhsXzeas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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