SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1d4c961cfbdddb7d90a3f6d765b554993c4904318a1ff30fe69094d10983ab6' 
  AND token = 'cGc442ed7dOkj6QvX+ZB3AzmQXvZ1iLlYMAVBRAdqlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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