SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1432fdc40dda39eb92f00ec925c4575dd34c96f6cb5f359929aca292ad21bd24' 
  AND token = 'K6UeHnhc8grK2exKqw/jpFsKCd8ipN+jXrphRIlR7cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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