SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc71e221cb4078cfbcda81cdcd0e819aaa716ffa6b8b2e6e0cf9f3fee60ce040' 
  AND token = 'WpUpqzcayPJQR+rjhmd9zX8BjzygT57PQC9spu7lGMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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