SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef40dfcbe812b3daf796623940baa466c8867583792b04af28714693794d87a4' 
  AND token = 'ABFiKmqpPunvxabvD9mZ31dbEja7dnOgH6LvoW6+bI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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