SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd364c0fe770b79d904954fabffd5f3f921609d7e182450938b5784328287541c' 
  AND token = 'dBL2+0KzP7XMJkhG44vXfdbC3FikMRKQfxPQ4YHrq1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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