SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4f7cf1e8147b7043e045671703f07c4241772ca45c1456fc8f9a0599436d08f' 
  AND token = '2bMgT/ZqNmTzvuFKY0ZT8LGYWMuNYtHEbj1vhbeqqNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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