SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d1db1c7085bcee211741298a0a19facb84266208537010d391c6ac6cc361f1f' 
  AND token = 'O82si80qqiWXnXZwcK1s7kdzadAfx8b3CBbHbsFX7Bs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}