SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ebbf7fd8bf09c499f475d0ff25924b946439b11c04393a7ea81157d1b4c280c' 
  AND token = 'IsMZ3APageeQLMm/qxk5tAvZYv2eRfm760JAxgG/NbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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