SELECT 
  1 
FROM 
  vi_lock_keys 
WHERE 
  key_id = 'df3aff8de3a25ae689ef58c867c135ba98434e09f81f36cc554f52ccd7d1f990' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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