SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d8523e272dd34daabb1d7eb13ed19cc087af7b6617a13d72a5563996b6eaae' 
  AND token = 'FS51JRxGo0HfN+pNNpgY+pldesia99ltRKbL7GGfXSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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