SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af259cc6fb6175ee1f945abc1f2b9e52c80911da5a348e39433de75d496633a9' 
  AND token = 'WXLIOVMif0C5EuhCF0iDwz8qVvQ/BrAT+y2BUFYDBRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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