SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbca3e8e668b0f4c127efafb82f8e336413525b08f5431324cabb4ee2b52f92b' 
  AND token = 'KgYj0ZpPSE/xvLWBowMnEkcUFnmZGJOZYdGG5PE3BBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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