SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2146ce831f42791a8c051c64a4ffeddfb581fad9757f649440108e2e523bfacc' 
  AND token = 'QNwo9XWsmU/cjbJzYoB6qN51jciXAO3xX9AS2JyXEFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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