SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45ab08ee1f1ccea077e7ceca157ceab2b012bde1d0c9cd1c63e54779d484de29' 
  AND token = 'oQUthhQz5Wd4bvdecNiiKxix7vVjolfi/hb8qBjQPLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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