SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8938005585325ad414155924292ce708ccca120f2183acad3368c9945106388' 
  AND token = 'L8oIPPn91wa0VYx5AGfDrlSMrnr1BoRPKCOozVvXRZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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