SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b38dbbc7a3c405d0e7ba05ea1611e5518220cf383519e9f2146eee8c0923f6a7' 
  AND token = 'xo52qDl3SDA+ZdyGfpOn63UflOG4ePdgYLWvFYF5D6s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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