SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d777882d2612a8c61595e38e774d85b9fcf98892ab371bfdfacbfef6004319e' 
  AND token = 'SZ7K4M1IjVsmcR817Zm+UiEcreWfcWicn4LbKh1gTjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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