SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '676738a472913c8f9f8ccf01bcfbeb009fcce4d93052e933f7ae49a4f0dbad40' 
  AND token = 'Q7ojbAgeiRKv1AhB/4qsebOqVJdG6q02iIkqi63sLyg=' 
  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"
    }
  }
}