SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f43535163f8ddbb312df2303a1ebedf3981606fe0aee8c235cce79002f9cf617' 
  AND token = 'RLpyUVqxnm8vhNgqMPsvO8wH4Z/rZRVwMw1yK18N+30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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