SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '931dd7dac5f73397a975ca1412e737951f04c9a6eca770f119529bceb466a576' 
  AND token = 'pQYe+qFjjgjTf7gEf+ZBrwcyOk0LswqTR6puaVxAoIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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