SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca70346a185f7b7bf8f355b20a73dc1f2970b0b2f690168c6263144e098d2378' 
  AND token = 'WmnH4ScnlxAUsz1mQEh4PAXyccPNMYI3JOH87xzoQ9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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