SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76f514cf3e0a85316a58225753ceeb26539f3cd3ad3b5350e4618a70623745d4' 
  AND token = 'tIPjz7P8BQqZo8avTYKJ0TUfzj48dvFn6Q1tiuzWZr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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