SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caffca0fda2145a1a6515650a6957ea91080fb40e7049c13688dec577a34d673' 
  AND token = '5pC0cUbhYI6vpefiUXqLVUTkQe4xU+/rvUpyqYgtHxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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