SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ae992c0902b5d097409bb927fbdbb9da25c49a69a4b2df0c391832d0a692b4e' 
  AND token = 'nVVwxWlQseBbmEct+N0TcWlUOqikq+vyHWpivxGylY0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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