SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92e5a50afac47b4679eec61c8157df6301381bdd2e6dab76f05d211e733ac80' 
  AND token = 't34/N8cFyXfHkDvF1Kmom/VFFMNlcOLQLFQ7ZmXtETs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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