SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd633dd42a88721495ee408a218a13f36c4294d12dd21d876f6a833faa5bef81d' 
  AND token = 'NqCZXoEZLOjfXW8JFKHqjV32zqy3WywkVnMZY3Za4kQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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