SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '21a18fd9b8fb150d50988dd1ca42bcb93d874f07740f1ecce950326f1dfbaa29' 
  AND token = '8DGpt0lE+oLL9dsXf0YmoyXVmJ6j/2dBht9RHTpZqR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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