SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '537e669262dbbc29231e80918826c732e2099cb20868535776ac7a3386f44934' 
  AND token = 'wIj63Waf5wcl4+/ZrgBaUnE7WFKBqsTDXTvCBk38s2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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