SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '897b5471e30996a70f5006293fb9b1bf437e7aa02d4fe3c54cf8b5fc283793f4' 
  AND token = 'aUIv0cZVbGybvMsFQuzeiWYPCjRBhln2+3JNIkaijyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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