SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceb6f2bb65e5ecfebdcdce7c4372e567b8bfc616ec0d452f0bf676e32ac74ec4' 
  AND token = '/0awfIlFV94v0+mV+10JDYnZ41BDYnTkgHiOxa2CSpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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