SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c38bd3531092ff988dd5a66dc7e1f41580aa767831076b602f412c26dbc6cf3' 
  AND token = 'Ou3iIDrZFrN3+SIa42Jf+WKXpdDJMbjjyj4VkIVZDl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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