SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa0bb35d9f0a53e89b82c702e9a55f16c948295d749a48d7a3e1f4479af24cfd' 
  AND token = 'iZICtT2aTZjVHzpm6tKgmgQq7VDZLs1zXUkzCWVSNOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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