SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c5cf9ad086f3a3f01dfa5689a880d28e2ecfa1890e9ad18773cfa08b6c33f2f' 
  AND token = 'tb5fR7tj+mDMNCziHFKqHjrLCWaLAfGeUCyOtGwHsRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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