SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a266ea42a54e3c3fefc5c48246577c628963ba1971ec649a8fda9eaff45e2c8' 
  AND token = '/Cqn6aImVifdwW8zl66H+8o+mzZVL8YKvP0WDzwlQnA=' 
  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"
    }
  }
}