SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df59835632d5fb6a5a1ea329086f86e9c00551f71b454bd3269732f7afd68412' 
  AND token = '0p8yx7CqMKv3DmHJ17TiUilJQJ3swFDBSzhnzX/g+ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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