SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39afcb0b1f295eb7c75b9baa9aa76f4c365433b6be6b3ad0809d8478fe4f64d6' 
  AND token = 'nryeSst7F8TgALziEe0xZ0gR731zPIlbR/yGWZZ35/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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