SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f6fffce2b1d0617b19baabbac1e3afea77f32812e12fd67fbe3a3a595777cb5' 
  AND token = '9bAuT2dcScexeqxcjFXtoZunv9SKpcLX4L/OgfJk3po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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