SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '305642dd4523af19541750da9a5c4478efe7a27c9438b131100d2905dcc34845' 
  AND token = 'XhlSZ/gBrRIK5XSpzdknaNpUaKs1+f98EA2em4CNGAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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