SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1901bfb93c97a23c6dbddc4bdf97c58a1acb389389dbddf85b3e56451004b8af' 
  AND token = '5y4rWsYLetAHIzj2gboDJ5Vax4omgarBVRv+PjyMOZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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