SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d10bb730f59500570147b67cf773a9e3244f125648cbedf82f34f9f6d632765' 
  AND token = 'PDbVwVFxuF+r69bqmZR+PYjZJBMYZoe76d3FHuDNJKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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