SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d9850bbe5b02ebc85170495e0352885390b8986def07194264d75bf7a8816fd' 
  AND token = 'NvBwOrJ4CP+zmwiH6hfYcuFD5NIsg553T8XBDw2jE+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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