SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd8d59fbf48ca977d329a8b6a29602e8517aa374152a48c8461e8d23cdee5052' 
  AND token = 'kGYTlXhDXWd1IW0GKCOPC32Wl25BWJjLZ1uE19YiqXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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