SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4294d0cdbf8523ca46e5286eaf28eaf996d7d39550151bc96f5d6250e5a7ee13' 
  AND token = '77KoBJBrfQkYKR9WohRON7vXFKQ8ucHOKrvb6IaYWtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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