SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2767dfb3a1272f045a6dbb028258229c0c3302f3face7a4eaa78d5d5b7f3b68' 
  AND token = 'PXcYvhrJr5rYIK9jxuEV1YOFyziYRaN+twSZ0P0+E/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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