SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf73ef2c85a6ab2c87314a7de60fd55b27c037a083bd2ed7b17a3cac109b49e8' 
  AND token = '+nXGjbWWnVKQKgtmnnCOEH2bHxRZdjkfH/Kw8z6Ttyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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