SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aea0f4ef119258140bfca10a43dc96263d5da293a9de3526ff5a8fddec301853' 
  AND token = 'UPrVXknLsp4/KWSCu2UdmwFrNuNRZB9lHZG2oUGo6rQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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