SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78c14ed403bc36ad277d3e9fcf10efe276afbfca4e5b460cad2731b7dd3a9763' 
  AND token = 'wGC+ys0GZt9q4LZj/uGBXe0FqJRuNVWFwwmytlZYyWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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