SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '045d5b136185283c040e909eac502a539a5179ef5c9d876ce3279da94ee44c05' 
  AND token = 'FaVQdfzzAf/cOe16YjC1lydXG6H8FEcONNleDKnf9Lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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