SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1e3079ff8db18747c5be96b1f26209acaa9d2896623942cad56d8682809ae09' 
  AND token = 'c3NA+VuXDn9mvL9lT3mjoGuMuIQUaJjnlrAdW+tlBVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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