SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '139f372f103d2e5e1d8d1d60716a52a751263f9b0e4aeb9ad3630ae695974031' 
  AND token = 'WhiG75KAM0JVu8UjWWuvVXOowK+0zPU/QuI+wdxb6ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}