SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '545ba8f4a7a6e7cc301cf85e3aa4b32bc1d4d6d705e58d610f4fc379e0270a63' 
  AND token = 'cONuTdTMJBeX7tf+2xe97UfnHji1V614oPv8hlQYsTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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