SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1df996b7da6aa87f06c715da45f5d3bf753c403c78db8306353e1939186caeda' 
  AND token = 'WlEcpT1v64KZbjwR1wLVqTG3+HxEPndmfvhMfavYhwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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