SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '813f1e19e75fa40419dc68278d02ec81461e4d07926f67455c2d36e2f5a6ab2a' 
  AND token = 'rLWm6x4eo+wBnAjadn40LJR61qhzunbL7PW7olMT7Yc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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