SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab95c4af4d9dbe6dfc6d8324c8eb9fc8d2e86636447819a5d74d790e5deb6698' 
  AND token = '/8JJSnoFnCfFzGUZedWRPxqu5y4nlm/RLclxoFttEFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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