SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec0913a9637fc78dfd4b1d0084e21ade328af6842b37a10bd64d7c5e8e523bd9' 
  AND token = 'wAYeHSOoEyLszNb5b2N0fmaQaN0vSqGE0l9YfesNlGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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