SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de82b58094ce762b077a756845563bff7351980bc5453543f6be7e9859820aa8' 
  AND token = 'B/p0Zv0NxpKjzgmWYVI5LoBRXAMsPw5rTtNgzHoEeLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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