SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a36d790e1a363688ab8983143c6f7c2f1ef17f510b8b2e301f06db621673215' 
  AND token = 'yHU/P/W3KBcCg4aqA2QvpqIVZI4hVq5oB352sZdLyFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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