SELECT 
  1 
FROM 
  vi_lock_keys 
WHERE 
  key_id = '6836c9b78fa3c3293d108ec2a78def270ed1fa6ba7d5a9087c609193fe7936c2' 
  AND token = 'V3Mwcd+Xg2FzHermqLVd9Lua+HgYT4UZn4hDByFx+Lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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