SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fe73a366ce3d45c9a8f9f05dc69cb28f2b0f3a573e57197bae208eecc5c209f' 
  AND token = 'pcx6H1CghNTN31NmCFWm3mGLDCq3MIrFnvWtifZtbhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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