SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4206235357989524cd9267dd4764974bd18dbb467fa855f9f5c5d245da23a766' 
  AND token = 'GgpOirb8LefB/p8uTzUO2LXwWeNLkrrj493rlKoG4Q0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}