SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9104086fc7c28624a1b1d434caea47b0a98d4007f0b89965ab4659c063b872d' 
  AND token = 'KIQBsH8stqdJXHf6hecbSIzY2/bbWZtx0QVAuAzMFqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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