SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1426d6b5ccc704076c280289b10326e0f9cc413318bc5f76a093ee9d3eea0499' 
  AND token = 'v9F/FegnONtBlhs45vbfYbmvH6CtRg5rnVao/KcY4Vw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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