SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c78d19980f01c37c7a4b888480fe21927378e6f3b91f1dc854c51e433fe98106' 
  AND token = '9KOLTL3SMv/izOgfKSXUVvYUQJ66MpQKelkOJlYjGNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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