SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b12bc57d4a8847b87423809e897a0428ab58c312ff65efc203e9c96ba0e61e6' 
  AND token = 'CyOfvzcmGNYEtjJtpLIw9V92JNXchhA4FWK5atgd5Xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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