SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4046f7e9138791f1ab517d31573689109b1f716a421615adead81673210b82dd' 
  AND token = 'JzA9pejQv1s6avkwEO7DSjflyPNN9BXIh3LUaxAgp38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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