SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '259b3428e72bc25287c33aff9a79a66b4b2aed53126ab5dfa25b3f3fd504e4e6' 
  AND token = 'RKj7AVqF4tAUCDnIDJ1pr3sqj3N6SZuFGzaGSnw+AFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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