SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2e3754e127f828afbd37fc1d6e23f6c7d0746d28a017b5491d956f02cc28d5a2' 
  AND token = 'PgZRmdLNMXtLC+EY4j9OYJWIJ3gGEPSb3enGOAPdRPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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