SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e261a74433cedb9dd8ac790f21c29bb39724f437138609ab7a2f1d1bec7ef0c9' 
  AND token = 'CnA58ZZi/23QyNywK4FhqfXLZHxUH6A+sVif3lLtKJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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