SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '541303178650dbec614d914001d168f4ff65726eb68e4b7b3c99c617f86f9a55' 
  AND token = 'q4phJu9Zi+kLr44dqMVWHM0pyXWvgIzFUTVYPH3wc+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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