SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e500d23e598aa01ca534c0cf2f8403b3777f238262a9582c8682caa5ae9e4c8' 
  AND token = 'V9mVSfuk38o51QvDtYVTvd+bVgKD6cqlOXQWOlJ5j2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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