SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ac1c2de2ba78533ddefe828afd36e57a7fba208026bc8d60cfc5a7e585f8d3' 
  AND token = 'PUX07pKSx794bUyucrUvrJqqmfrGfgCgkr2jW9iRXMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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