SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14bb351ba0af682e189fcce0206ee23681a336e724c2b05917ba30e3cf34dbce' 
  AND token = 'lso4TjwqQCXv+8VsJEzGntg6JZesdMZ8EoUhLBueZIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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