SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '690ba29da1aff375284a468168447e7762dc104cdea425462b6f99b6c2f8aafa' 
  AND token = '9bpQBmi5NUAaaUij8zU9a/Y73JGdqm84xdYUN4j69M4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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