SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad992977b4f38bf702b70354c377a68ec75c6e3fa5f3562cbabf38567ce7ab53' 
  AND token = 'TVSP9z2j3rKNRZUupSGmbXbbb119wzYFXuQ0kPsr6vg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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