SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dda694f9fcc97081c89fcb1bdb19475d28d5fdd9923cd65e040d8d6e73466e1' 
  AND token = 'tHB7MxmKM3U6ptnzQvFBkuJxcGwvVG56J54G6+Rishk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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