SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a3f7318d71cb036f5035c0d2bce97559f7b6313706b6bb7be2f4e06fc3713dc' 
  AND token = 'ozruAhZJi0JCb8IOjAUc3AR51cHOYfHVoMGUxRBuafs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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