SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b598de164c2f2dcba40f603bc215870f3908f9467bbd3f3739ab40a718b7e294' 
  AND token = 'Hxv3u/XNm8GV+kSQtaub4AcYK0QhgKEXWJJmaTZI5cY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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