SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75327e996cc05552b531b93487df3b0f3a5bf2e9cb9e4f4a1c5a896e8a02f9b4' 
  AND token = 'nlJVQPRQZ5VUPhXg1z9WKZLuwHUmBAqSirxQ8Pseo7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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