SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2deabde3a28b6407407e9c8f235d34d13b6028cc56d5ddf6807393a42e57361e' 
  AND token = 'pM7nXaO6j120MzECVG590CjuQ5avlmjH3U1UwOokZfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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