SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ce139d3ad1cfa55c6eb3d55238ee50a4469340e51b4b72069b0f8f4e87350d4' 
  AND token = 'xtB2ppblvHqHyvRGJd1KjO5aV7/3HhVB42yhwzKGNfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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