SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5a9a27982953f5450cf8409bcf8ffa524d6d9a191cc58f2ace2c90e27911f10' 
  AND token = 'PrRTTSsROsS1nDxUBlzkfD/9wTjtv1m3ifSGpTUS6nI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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