SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e272dc5ac94aa112c2171e1e670831c9e33a0b15cfbe398112d59ae957cf971d' 
  AND token = 'kJEpyuO+zxtbQO/X3dfH10wytqhihieR6SEqjieoi4g=' 
  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"
    }
  }
}