SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c3bd39ca9709fdb414fb9a83d0d9035736900003e556b2279785ec71e2f3573' 
  AND token = 'CnTSgLiDd6pVDe+1QfXQF9FiMPc+A3vd1GMQhWUhUNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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