SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0af758e6c6b8bf171b973d8638dfa6639fc3d4416f62ab47c487b69038d1b3d' 
  AND token = 'h2Lju7JpSNmjRQPlnOrz4cK+ELoXAS7RwUIuZhlx/a8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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