SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991513e5e06f86ae0d40d13bebc3ebf113a0d5e74927494854de589cc5994ccd' 
  AND token = 'YjsJSau1mXZjVslAq3RXpqkvVxIuoGyUPaWJApbqsfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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