SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc573fca825fbadb289d671c8a612755c64c91991ee5fd687df9b9d3f9c21560' 
  AND token = 'VnT+cJWlDVAGxpOqyJCDcaWPqprA5fRVwWz6nk1cHGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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