SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '447ab1b48ebf62097009ba5c60716c2da0ef709007799fa0c9a0651d51845830' 
  AND token = '47VBtyuBn+KA+Wv8MKJh/jF7XFJdzadUNaPYPbSBJRI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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